Rising sea levels amplify the threat and magnitude of storm surges in coastal areas. The U.S. east coast region north of Cape Hatteras has shown a significant sea level rise acceleration and is believed to be a “hot-spot” for accelerating tidal flooding. To better understand the forcing mechanism of long-term regional sea level change, in order to more efficiently implement local sea level rise adaptation and mitigation measures, this work investigated the teleconnections between low-frequency sea level variability in the coastal region north of Cape Hatteras and the subpolar/tropical North Atlantic Ocean by using tide gauge measurements, satellite altimetry data and a sea level reconstruction dataset. The correlation analysis demonstrates that the tide-gauge measured sea level variability in the area north of Cape Hatteras is highly and positively correlated with that observed by satellite altimetry in the subpolar and tropical North Atlantic between 1993 and 2002. Over the following decade (2003–2012), the phase of the teleconnection in the subpolar region was reversed and the spatio-temporal correlation in the tropical North Atlantic was enhanced. Furthermore, the positive correlation in the region north of Cape Hatteras’s near shore area is strengthened, while the negative correlation in the Gulf Stream front region is weakened. The North Atlantic Oscillation and Atlantic Multidecadal Oscillation, which affect variations of the Atlantic Meridional Overturning Circulation and Gulf Stream, were shown to have significant impacts on the decadal changes of the teleconnections. Coherent with satellite altimetry data, the reconstructed sea level dataset in the 20th century exhibits similar spatial correlation patterns with the Atlantic Meridional Overturning Circulation, North Atlantic Oscillation and Atlantic Multidecadal Oscillation indices.

Residual current analysis of multiple stations’ periodic observational data for sea currents, and multiple voyages, multiple seasons from 2018 to 2022, revealed the existence of a strong southwest current zone, 20–30 m underwater and within the coastal current area of Yangjiang, western Guangdong, in the northwest region of the South China Sea. The velocity of the residual currents in the strong–current zone was 38.2–100.3 cm/s. Observational data for wind, sea currents, salinity and tide from multiple coastal stations in the spring (from March 2019 to May 2019) and summer (from June 2019 to August 2019) of 2019 demonstrated the existence of abrupt strong currents in the coastal current sea area of Yangjiang, western Guangdong. Analyses of continuous sequence hydro meteorological data for the Yangjiang area indicated that wind stress was the main factor determining the direction of sea currents; increases in the near-shore water level produce a westward geostrophic current and a wind current in the shallow sea area; their joint effect was the key factor determining the velocity of the coastal current in this sea area. In spring and summer, when Pearl River runoff into the sea reaches a peak, and under the action of the northeast wind, the water level on the west coast of Guangdong rose. This created a barotropic pressure–gradient force from the shore to the outer sea, generating a southwestward geostrophic current in the same direction as the wind-driven current. The joint action of the wind-driven and geostrophic currents then generated a sudden southwestward coastal current.

We present geological, bulk-rock geochemical and Sr–Nd–Hf isotopic data for mafic rocks from the West Philippine Basin (WPB). These mafic rocks comprise pillow basalts characterized by a vesicular structure. The mid-ocean ridge basalt (MORB)-normalized trace element patterns of basalts from the study area display depletions in Nb. In addition, the chondrite-normalized lanthanide patterns of basalts from the WPB are characterized by significant depletions in the light lanthanides and nearly flat Eu to Lu segments. The investigated rocks have initial ⁸⁷Sr/⁸⁶Sr ratios (⁸⁷Sr/⁸⁶Sr(i)) of 0.703339–0.703455 and high ε_Nd(t) values (8.0 to 8.7). Furthermore, basalts from the WPB have ¹⁷⁶Hf/¹⁷⁷Hf ratios that range from 0.28318 to 0.28321 and high ε_Hf(t) from 15.2 to 16.3. Semi-quantitative modeling demonstrates that the parental melts of basalts from the study area were derived by ~20% adiabatic decompression melting of a rising spinel-bearing peridotite source. The Sr–Nd–Hf isotopic compositions of basalts from the WPB indicate that their parental magmas were derived from an upper mantle reservoir possessing the so-called Indian-type isotopic anomaly. Interpretation of the isotopic data suggests that the inferred mantle source was most likely influenced by minor inputs of a sediment melt derived from a downgoing lithospheric slab. Collectively, the petrographic and geochemical characteristics of basalts from the study area are analogous to those of mafic rocks with a back-arc basin (BAB)-like affinity. As such, the petrogenesis of basalts from the WPB can be linked to upwelling of an Indian-type mantle source due to lithospheric slab subduction that was followed by back-arc spreading.